Embodiments of the disclosure relate to an autofocus apparatus and method for a camera, and more particularly, to a camera controller using face detection, an autofocus method of a camera, and a system including the camera controller.
Autofocus is a function of automatically focusing on an object and provides faster and more accurate focusing than manual focus. Autofocus mode may be largely divided into active mode and passive mode according to whether a range sensor is used or not. The active mode uses a range sensor including an ultrasound or infrared transceiver, which is specially provided apart from an image sensor, to calculate a distance of an object from a camera and calculate a lens position for correct focus based on the distance. Autofocus performance varies with the accuracy of the range sensor. When a high-priced range sensor is used to achieve high autofocus performance, manufacturing cost increases. The passive mode analyzes an input image to calculate a lens position for correct focus. The passive mode is divided into phase detection mode which uses a phase difference sensor to calculate a phase difference of an image and calculate a lens position from the phase difference and contrast detection mode which measures a contrast of an image while moving a lens within a predetermined range and seeks a lens position giving the highest contrast. The contrast detection mode which does not use a phase difference sensor needs to move a lens until a maximum contrast is detected, thus requiring a relatively long time to achieve correct focus. In addition, accuracy greatly varies with the design of a contrast filter.